Actuating and control system for gas-operated fog horn

ABSTRACT

An actuating and control system for a gas blown fog horn including a source of liquified gas. The liquified gas is in continuous communication with an inlet plenum. An outlet plenum is provided which is in continuous communication with the fog horn. Operator control means controls communication between the inlet plenum and outlet plenum and when actuated places said plenums in communication so that the horn is blown. Additionally, an automatic pressure operated blow control means is provided and can be selectively operated for periodically and automatically transferring pressurized gas from the source to the fog horn.

United States Patent Greene 1 1 Feb. 13, 1973 ACTUATING AND CONTROL SYSTEM FOREIGN PATENTS OR APPLICATIONS FOR GAS-OPERATED FOG HORN 473,294 3/1929 Germany ..1 16/142 PF [75] Inventor: Leonard M. Greene, White Plains,

N.Y. Primary Examiner-Louis .l. Capozi Att0rneyl(irschstein, Kirschstein, Ottinger & Frank [73] Assignee: Safe Flight Instrument Corp., White Plains, 57 ABSTRACT [22] Filed: March 10, 1971 An actuating and control system for a gas blown fog Appl. N0.: 122,770

[52] US. Cl. ..1 16/137, 92/5, 116/22, 116/70,116/112 [51] Int. Cl. ..G10k 5/00 [58] Field ofSearch....116/70,117,142, 65,142 FP, 116/137, 112, 22, 24, 55; 340/388; 91/1; 92/5 [56] References Cited UNITED STATES PATENTS 2,396,423 3/1946 Hines ..1 16/142 F? 2,468,483 4/1949 Chambers et a1 ..1 16/22 3,066,641 12/1962 Buell, Jr. et al. ....116/1l2 3,269,352 8/1966 Van Winkel ..1 16/65 horn including a source of liquified gas. The liquified gas is in continuous communication with an inlet plenum. An outlet plenum is provided which is in continuous communication with the fog horn. Operator control means controls communication between the inlet plenum and outlet plenum and when actuated places said plenums in communication so that the horn is blown. Additionally, an automatic pressure operated blow control means is provided and can be selectively operated for periodically and automatically transferring pressurized gas from the source to the fog horn.

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SHEET 2 [3F 2 F I G 6 4 INVENTOR. F! G. 4 LEONARD M. GREENE BY haw/em mall/ L "ttlw f fhfim K ATTORNEYS ACTUATING AND CONTROL SYSTEM FOR GAS- OPERATED FOG HORN BACKGROUND OF THE INVENTION l. Field of the Invention A fog horn control system for enabling a fog horn to be periodically and automatically blown or blown when desired.

2. Description of the Prior Art Fog horns have been used for many years by boats for providing warning signals when visibility is limited with the fog horn producing the signal upon being supplied with a source of energy. Many fog horns used and now use gas under pressure as a source of energy and unless specified to the contrary all reference herein is to a fog horn using a gas under pressure as its source of energy. Usually the gas was kept in a tank with spent tanks being replaced by charged tanks as required.

The prior art taught many control systems for regulating the supply of pressurized gas to a fog horn to produce the required audio signals. Many of these prior art systems utilized electrical control means that were difficult to maintain in workingcondition over long periods of time. Some systems used batteries which frequently required replacement limiting their usefulness. A drawback of gas operated fog horns was that not all the gas was used in blowing the horn. This resulted in gas being used inefficiently and required more frequent replacement of spent tanks with charged tanks. A further drawback of prior art fog horn control systems was that as the gas in the tank became spent the signals from the fog horn became weaker and weaker and were thus ineffective for their intended purposes.

In heavy fog it is desirable that means-be provided for producing a series of audio signals by automatically blowing a fog horn periodically to continuously warn of the presence of the boat on which the fog horn is located. It is desirable that the duration of each signal (blow) be the same as well as the period between signals. of course', it is also necessary that means be provided for blowing the fog horn as required. In addition the blow can be initiated and terminated under manual control.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an improved control system for a fog horn.

A still further object of the present invention is to provide an improved control system for a fog horn wherein the system can automatically blow the fog horn to produce a signal periodically with selectively operable control means provided for blowing the horn when desired.

Another object of the present invention is to provide a control system for a fog horn so that the horn can be blown periodically between equal length intervals with the duration of each blow being the same.

Yet a further object of the present invention is to provide a control system for a gas-operated fog horn wherein all the gas used in the control system is used for blowing the fog horn.

A still further object of the present invention is to provide an improved control system for a fog horn capable of achieving the above and other objects and which does not require electrical energy to operate.

Briefly, in accordance with the present invention, the above as well as other objects are achieved by a control system which is connected to a gas-operated fog horn. The control system includes a supply tank containing a liquified gas under pressure. The supply tank is in continuous communication with an inlet plenum which in turn is in continuous communication via an orifice with a timing chamber. The timing chamber is a closed chamber having a plurality of rigid walls with an enlarged opening in one of said walls. A prestressed spring diaphragm closes said opening and an automatic blow control is provided which can maintain the diaphragm extended through the opening in a first position (snapped-in position). Alternatively, the automatic blow control can be positioned to allow the diaphragm to be snapped to a second position (snapped-out position) when the pressure in the chamber is above a predetermined level. Attached to the diaphragm is a kinematic train including a lost-motion linkage. A first valve is secured to the kinematic train and controls flow through an opening between the timing chamber and an outlet plenum, the latter leading to the fog horn. Part of the kinematic train extends into the outlet plenum and a spring in the outlet plenum is secured thereto. A rod is secured to the spring and can be moved by a manual control means which is outside the outlet plenum. Secured to the rod is a bell crank lever which controls communication between the inlet plenum and outlet plenum by regulating the position of a second valve in an opening which is in communication with both of said plenums.

In operation, gas from the tank enters the inlet plenum and through the orifice communicating the inlet plenum and timing chamber passes to the timing chamber. When it is desired to manually operate the system the automatic blow control is positioned so the diaphragm is maintained in the first position with the first valve preventing communication between the timing chamber and the outlet plenum. The manual control means is then moved, shifting the rod against the bias of the spring. Consequently, the bell crank moves the second valveto open position so that the inlet and outlet plenums are in communication. Since the outlet plenum is in communication with the fog horn, the gas which is directed thereto from the inlet plenum is transferred to the horn which is blown. As long as the manual control means is operated as described the horn will produce a signal, and when the manual control means is no longer so operated the spring which is connected to the kinematic train and the rod moves the rod and bell crank lever so the second valve prevents communication between the plenums.

When it is desired to have the horn automatically blown at defined intervals the automatic control is moved to a position where the spring diaphragm can snap outwardly with respect to the wall to which it is attached when the pressure in the timing chamber is above a predetermined level. As a result of the gas in the timing chamber which is in continuous communication with the inlet plenum the pressure in the chamber is above the predetermined level and the diaphragm moves outwardly of the wall to which it is attached taking up the lost motion in the kinematic train so that the first valve allows leak flow from the timing chamber to the outlet plenum. The taking up of the lost motion moves the bell crank lever and opens the second valve to connect the inlet and outlet plenums. Consequently, the horn produces a signal which principally is produced by gas flowing from the inlet to the outlet plenum. The opening of the first valve through which communication between the timing chamber and outlet plenum is achieved is substantially larger than the orifice which controls the flow of gas from the .inlet plenum to the timing chamber. As a result, after a brief interval of time, e.g., three-fourths second, the pressure within the timing chamber drops so the diaphragm moves in a snap action to the first position. This moves the first valve to a position preventing communication between the timing chamber and outlet plenum and the second valve to a position preventing communication between the inlet and outlet plenums. Consequently, no gas is directed to the timing chamber through the inlet plenum and the orifice which communicates the inlet plenum and the timing chamber. When the pressure in the timing chamber is sufficiently high the diaphragm snaps to the second position and the cycle is once again repeated.

In another embodiment of the invention only the timing chamber is communicated to the outlet plenum when the system automatically and periodically blows the horn so that the gas stored in said chamber is solely relied upon to energize the horn for each blow.

Other objects of the invention will be pointed out hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangements of parts which will be exemplified in the devices hereinafter described and of which the scope of application will be indicated in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a cross-sectional view of an embodiment of the present invention;

FIG. 2 is an enlarged cross-sectional view of the inlet and outlet plenums of the present invention;

FIG. 3 is an enlarged cross-sectional view of the diaphragm structure of the present invention;

FIG. 4 is a cross-sectional view of an alternate embodiment of the present invention;

FIG. 5 is an enlarged cross-sectional view of the inlet and outlet plenums of the embodiment of FIG. 4; and

FIG. 6 is an enlarged cross-sectional view of a segment of the timing and supply chamber structure of the embodiment of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 a fog horn 10 is shown that may be conventional and will produce an audio signal upon a gas under pressure being directed thereto. The control and actuating system for fog horn 10 includes a supply tank 12 which contains a liquified gas. While any gas, such as carbon dioxide, etc., may be used excellent results can be obtained with Freon l2 (dichlorodifluoromethane).

Tank 12 may be a conventional gas supply tank such as can be purchased at boating and supply stores and is connected by a conduit 14 having a choke 14a therein to an inlet plenum 16. An outlet plenum 18 is separated from inlet plenum 16 by a partition 20. An opening 20a is in said partition and as hereinafter will be described allows communication between the inlet plenum and outlet plenum.

Inlet plenum 16 is defined by a portion of wall 21a, partition 20, a wall 21b, a portion of wall 22a, as well as by end walls which are not shown in FIGS. Outlet plenum 18 is defined by a segment of wall 21a, wall 21d, partition 20, a portion of wall 22a, as well as by end walls which are not shown in the FIGS.

A timing chamber 22 is defined by a plurality of walls, four ofwhich canbe seen in FIG. 1 (22a, 22b, 22c, 22d). It is, of course, to be appreciated that end walls assist in defining the volume of timing chamber 22 but are not shown in the'FIGS. Wall 22d includes an opening which is spanned by a prestressed spring diaphragm 24. An'automatic blow control 26 is provided and includes a cam 26a which is rotatable by a handle 26c about an off-center pivot point 26b. Offcenter pivot point 26b is formed on bridge 27 which is secured to wall 22d. When the automatic blow control is moved to the position shown in the dotted lines diaphragm 24 is in the position seen in solid lines in FIG. 1 (the snapped-in position). When the automatic control is moved to the position seen in solid lines the diaphragm is in the position seen in dotted lines (the has a substantially larger cross-section than orifice 28 for a reason that will soon be readily apparent, but is smaller than opening 20a.

Secured to diaphragm 24 is a kinematic train including a link 32a rigidly secured to said diaphragm. A second link 32b is secured to first link 32a by a lost motion connection L and can move a short distance relative thereto before the lost motion is taken up. Link 32b extends through opening 30 to a stiff coil compression spring 34 in outlet plenum 18. Movable with link 32b in timing chamber 22 is a valve 36 which can seal opening 30 as will hereinafter be described.

A control rod 38 is joined to spring 34 and extends through wall 21a. A manual control push button 40 is attached to the end of rod 38 which is located outside outlet plenum 18. A conduit 42 provides continuous communication between outlet plenum 18 and horn l0. Secured to rod 38 is a bell crank lever 44 which is pivotal about a fixed pivot point 44a. A rod 46 is pivotally secured to the free end of the horizontal portion of the bell crank and extends through opening 20a to a valve 48 which is secured thereto. Valve 48 controls communication between inlet plenum l6 and outlet plenum 18 through opening 20a as will hereinafter be readily apparent.

When it is desired to deactivate the fog horn, handle 26c is placed in the off position seen in dotted lines in FIG. 1 and diaphragm 24 is in the snapped-in position shown in solid lines in FIG. 1. With the diaphragm in this position valve 36 cannot move to communicate chamber 22 with outlet plenum 18. Gas from tank pressurizes inlet plenum 16 via choke 14a and timing chamber 22 via orifice 28.

Depression of button 40 results in rod 38 moving to the right compressing spring 34. Link 32b does not move to the right since with the diaphragm in the snapped-in position link 32a cannot move to the right as all the lost motion between said links is taken up. As

a consequence of the movement of rod 38 to the right bell crank 44 is rotated in a clockwise direction about pivot point 44a with rod 46 being lowered and valve 48 moving away from the position seen in FIG. 1 so that inlet plenum 16 and outlet plenum 18 are in communication via opening 20a. Thus pressurized gas is transferred to outlet plenum l8 and communicated via conduit 42 to fog horn 10 which is blown. As long as button 40 is depressed the fog horn will blow and the removal of pressure from the button allows spring 34 to move rod 38 to the left so thatbell crank 44 rotates in a counter clockwise direction about its pivot point and rod 46 moves upwardly with valve 48 closing communication between the inlet plenum and outlet plenum.

When it is desired to have the fog horn automatically blown at periodic intervals handle 260 is placed in the position shown in solid lines and cam 26a is in the on I position shown in solid lines.

If the horn has not been periodically blown for some time the pressure in the. timing chamber is sufficiently great to snap diaphragm 24 to the position shown in dotted lines. It is to be appreciated that the diaphragm does not move to the position shown in dotted lines from the position shown in solid lines until the pressure in the timing chamber is sufficiently high to overcome the resiliency of the diaphragm and the atmospheric pressure acting on the outside surface thereof.

If the horn has been on automatic operation recently the pressure in timing chamber 22 may not be sufficiently high to move the diaphragm to the snapped-out position when handle 260 is placed in the position shown in solid lines in FIG. 1. However, after a short passage of time the flow of gas from inlet plenum 16 via orifice 28 to timing chamber 22 will increasethe pressure therein so that the diaphragm will move to a snapped-out position.

When the diaphragm moves to the snapped-out position link 32a moves to the right taking up the lost motion between it and link 32b and moving valve 36 to the right, uncovering leak opening communicating timing chamber 22 and the outlet plenum. The rightward movement of link 32b applies a tension to spring 34, moving rod 38 to the right and rotating bell crank 44in a clockwise direction so that the inlet plenum and outlet plenum are communicated. The gas in inlet plenum flows through opening 20a into outlet plenum 18 from which it discharges via conduit 42 to horn 10 which is blown. Opening 20a is larger than opening 30 and most of the gas which blows the horn comes from the inlet plenum. After a short interval of time, e.g., threefourths second the discharge of gas from chamber 22 as just described reduces the pressure therein enough for the atmospheric pressure acting on the outside surface of the diaphragmand the prestressing thereof causes it to suddenly shift to snappedl-in position. It is to be recalled that the cross-section of orifice 28 is smaller than the cross-section of leak opening 30 so that when valve 36 does not block opening 30 the pressure in the timing chamber rapidly decreases. With the valve 36 closed the pressure in the timing chamber slowly builds up, e.g.. 1% minutes, and the cycle is repeated.

The lost motion between links 32a and 32b is provided so that'as pressure builds up in timing chamber 22 and deflects the diaphragm before it snaps out the positions of the valves 36 and 48 are unaffected. Choke 14a is so selected that the pressure in the outlet plenum will not be above a certain level adversely affecting the timing and possibly preventing the diaphragm from moving to a snapped-in position.

It should be noted that the duration of blow of horn 10 is relatively constant as well as intervals between blows. The intervals between the blows is determined by the size of the timing chamber as well as the size of opening 30 and to a lesser extent by the size of orifice 28. The timing may slowly shorten between blows on automatic operation for the first 15 or 20 minutes until the pressure of the saturated vapor from tank 12 is stabilized inasmuch as the boiling off of liquid lowers the liquid temperature and, therefore, the tank pressure. Except for the initial blow which may be longer due to the initially higher pressure of gas in chamber 22 during periods of non-use of the automatic blow feature because the liquid temperature is at ambient temperature, the blow times will not change significantly when stabilization is reached while the intervals between blows will slightly progressively increase until stabilization is reached and then stay constant. The blow interval and blow time is also determined by the operating pressure differential of the diaphragm.

1n the embodiment of the invention shown in FIG. 4, supply tank 12 via non-choked conduit 14 and a passageway 98 leads to an inlet plenum 100. A partition 102 separates inlet plenum from an outlet plenum 104 and an opening 103 extends therethrough. The inlet plenum 100 is defined by a segment of partition 102, a portion of walls 106 and 108, as well as by wall 112. Outlet plenum 104 is defined by a portion of wall 105, a portion of wall 106, a portion of wall 108 and a segment of partition 102.

An orifice 113 in wall 1 12 places inlet plenum 100 in continuous communication with a timing and supply chamber 114. The timing and supply chamber is defined by walls 108, 112, 116, 118 and portions of walls and 106. Wall 105 includes an opening which is spanned by a snap spring diaphragm 120 that is identical to diaphragm 24. An automatic blow control 122 is provided, and includes a cam member 124 which is rotatable about an offset pivot point 124a. A bridge 127 which spans the opening in wall 105 supports the automatic blow control structure. A handle 128 rotates cam 124 as will hereinafter be described. Attached to diaphragm 120 is a kinematic train 130 that includes a lost motion L which may be conventional, and movable with the end of the kinematic train furthest from diaphragm 120 is a valve 132. Valve 132 regulates the communication between timing chamber 114 and passageway 134 which leads to outlet plenum 104.

A rigid rod l36'extends through wall 105 of outlet plenum 104. Attached to the external end of rod 136 is hand push button 138 and a spring 140 surrounds the portion of rod 136 that is adjacent the outside surface of wall 105. Spring 140 is a compression spring and biases rod 136 to the closed position seen in FIG. 4. Rod 136 extends through opening 103 and a valve 144 is secured thereto.

In off position of the blow control 122 (solid line position) the liquified gas in tank 12 which may be Freon 12 or any other suitable gas, is communicated via conduit 14, passageway 98, inlet plenum 100 and orifice 113 to chamber 114 where it builds up to tank pressure. If it is desired to manually blow horn 10, push button 138 is moved towards wall 105. Spring 140 is compressed and rod 136 moves so valve 144 does not block opening 103 and the gas in inlet plenum 100 is directed to outlet plenum 104 and to the horn. As long as button 138 is depressed the horn will be sounded. When the button is no longer depressed, spring 140 will move rod 136 to the position seen in FIG. 4 and valve 144 will prevent communication between inlet plenum 100 and outlet plenum 104 so that the horn will no longer be supplied with a source of energy.

When it is desired to have the horn automatically blown handle 128 is moved to the on position seen in dotted lines in FIG. 4, and if the pressure in chamber 114 is above a predetermined amount the diaphragm moves to the snapped-out position seen in dotted lines. If the horn has not been on automatic blow recently the pressure in the chamber will be above the predetermined amount but if the horn has recently been on automatic blow the pressure may be below the predetermined amount. However, the transfer of gas from the inlet plenum to the chamber via orifice 113 will increase the pressure to above the predetermined amount and the diaphragm will move to the snappedout position seen in dotted lines. As the diaphragm snaps out the kinematic train moves, the lost motion is taken up and valve 132 opens to provide communication between chamber 114 and passageway 134. Accordingly, the gas in the chamber is directed dumped) from the chamber 114 via the passageway, outlet plenum 104 and conduit 42 to horn 10 which is blown.

After a short interval of time, e.g., three-fourths second, as a result of the discharge of gas from chamber 114 as just described, the pressure in the chamber is sufficiently low so that the atmospheric pressure acting on the outside surface of the diaphragm and the prestressing thereof causes the diaphragm to snap to the position seen in solid lines in FIG. 4. The pressurized gas from tank 12 continues to be directed to chamber 114 via orifice 113 and the pressure in said chamber slowly builds up, e.g., in 1% minutes, until the diaphragm moves to snapped-out position and the cycle again repeats. It is to be noted that in the embodiment of the invention disclosed in FIGS. 4, 5 and 6 chamber 114 acts as a supply chamber and timing chamber in that all the gas used in automatically sounding the horn during a blow comes from this chamber in which it previously was stored.

In the embodiment of the invention of FIGS. 1, 2 and 3 chamber 22 acts primarily as a timing chamber since the major portion of the gas for blowing the horn comes from the inlet plenum and through opening 200 which is substantially larger than leak opening that leads from chamber 22 to outlet plenum 18. As a result of chamber 114 acting as both a timing. chamber and a supply chamber it is of necessity larger than chamber 22 of the embodiment of FIGS. 1 through 3. The control structure of FIGS. 1, 2 and 3 is smaller, more reliable and uniform in operation than the control structure of FIGS. 4, 5 and 6 and is, therefore, preferred. However, the structure of FIGS. 1, 2 and 3 involves slightly more complex mechanisms. In the embodiment of the invention shown in FIGS. 4, 5 and 6 the blow time is highly dependent upon the characteristics of the horn because only the gas accumulated in the supply chamber is available for actuating the horn; whereas the particular type of horn utilized with the control system of FIGS. 1, 2 and 3 does not greatly effect the blow time of the system disclosed in those figures since the supply of actuating is only limited by the gas available in the tank.

In both embodiments of the present invention the pressure in the systems acts to close the valves so that leakage is minimized. The supply or power source for the device is a tank of compressed liquified gas. The saturated vapor pressure at the top of the tank is dependent upon the temperature of the contents of the tank. Therefore, the operating pressure varies with the ambient temperature. The ambient temperature effect is not as important however, as the temperature, and therefore the pressure, drop due to using the gas which boils from the liquid. For practical purposes for this use the saturated vapor pressure stabilizes at some value (lower than the normal pressure present due to a long stabilization period at ambient) determined by the amount of gas boiled off per unit time. In the description, it will be assumed that the horn is specified and that the normal signal time is three-fourths second and that the interval between signals is approximately 1% minutes. On an average day, these conditions will result (for Freonl 2) in a vapor pressure of 40 lbs. per square inch.

The device will operate uniformly until the last drop of liquid in the tank is used; there will be no drawn out weakening of the horn sound as the liquid level drops as there would be if a compressed but not liquified gas is used. It has been observed that a standard 15 ounce can of Freon-l2 will support more than 3 hours of operation of a conventional gas horn.

It should be noted that in both embodiments of the invention the horn can be manually blown even if set on automatic blow control.

The following dimensions are given by way of example in connection with the two specific embodiments of the present invention' None of these dimensions are critical: however they have been given in order to amplify the disclosure and to aid in constructing said embodiments.

In FIGS. 1 through 3 the sizes of the plenums l6 and 18 do not affect the blow and idle periods as long as they are large enough. The inlet plenum 16 may be 3 cubic inches and the outlet plenum 18 6 cubic inches. The timing chamber 22 is 10 cubic inches, the interval timing orifice 28 has a diameter of 0.0015 inch and the blow time orifice 30 has an equivalent diameter of 0.016 inch. The term equivalent diameter is used here inasmuch as the orifice has a link 32b extending through it. The opening 20a between the inlet and outlet plenums may be of any size and by way of example is one-fourth inch in diameter. The choke 14a has a diameter of one-sixteenth inch. The relative proportioning of the interval timing orifice 28, the blow time orifice 30 and the volume of the timing chamber 22 determine the values of the blow and idle times of the fog horn.

Concerning the embodiment of FIGS. 4 through 6, the size of the inlet and outlet plenum chambers 100 and 104 are not important, and may be by way of example 3 and 6 cubic inches respectively. The volume of the interval timing chamber is l8 cubic inches. The diameter of the supply chamber 114 which is an interval timing chamber is l8 cubic inches. The diameter of the interval timing orifice 113 is 0.025 inch. The diameter of the opening 103 is not important and is by way of example one-fourth inch. The diameter of the opening 103 is not important and is by way of example one-fourth inch. The diameter of the rod 136 is one-sixteenth inch, and the diameter of the valve 132 is oneeighth inch. In this embodiment of the invention the parameters which determine the blow and idle times of the fog horn are the volume of the timing chamber 114 and the diameter of the interval timing orifice 1 13.

It thus will be seen that there is provided a device which achieves the various objects of the invention and which is well adapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiments above set forth, it is to be understood that all matter herein described or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described the invention there is claimed as new and desired to be secured by Letters Patent:

1. A control system for a gas blown fog horn having as a source of energy a pressurized gas comprising: an inlet plenum, means for continuously communicating said inlet plenum with a source of pressurized gas, an outlet plenum, means for continuously communicating said outlet plenum to a fog horn, operator control means for placing said inlet plenum and said outlet plenumin communication, and pressure responsive means selectively operable for periodically and automatically transferring pressurized gas from a source of pressure to a fog horn with said pressure responsive means actuatable'by pressurized gas from a source of pressure to a fog horn, said selectively operable means including a chamber, said chamber in continuous communication with said inlet plenum and means responsive to the pressure in the chamberfor periodically transferring pressurized gas in said chamber to a fog horn.

2. A control system for a gas blown fog horn having as a source of energy a pressurized gas comprising an inlet plenum, means for continuously communicating said inlet plenum with a source of pressurized gas, an outlet plenum, means for continuously communicating said outlet plenum to a fog horn, operator control means for placing said inlet plenum and said outlet plenum in communication, means selectively operable for periodically and automatically transferring pressurized gas from a source of pressure to a fog horn, said selectively operable means including a chamber, said chamber in continuous communication with said inlet plenum, means responsive to the pressure in the chamber for periodically transferring pressurized gas in said chamber to a fog horn. said selectively operable means further including passage means communicating said chamber with said means for continuously communicating said outlet plenum to a fog horn, said periodic transferring means a flexible elastic member movable by the pressure in said chamber, valve means for open ing and closing said passage means and a kinematic train connecting said flexible elastic member and said valve means.

3. A control system according to claim 2 wherein said kinematic train includes lost motion.

4. A system according to claim 2 wherein means is provided for keeping said flexible elastic member in a position wherein said valve means closes said passage means.

5. A system according to claim 2 wherein said flexible elastic member is a diaphragm, said chamber defined by a plurality of walls, one of said walls having an opening therein, said diaphragm secured to said wall so as to span said opening, said diaphragm prestressed so that when the pressure in said chamber is less than a predetermined amount the diaphragm snaps to a position wherein said valve means closes said passage means.

6. A system according to claim 5 wherein said passage means communicated said chamber to said continuous means through said outlet plenum.

7. A system according to claim 6 wherein said operator control means includes an opening extending between said inlet plenum and said outlet plenum, a valve for controlling the flow through said opening, and means manually operable for moving said valve to regulate the flow through said passageway.

8. A system according to claim 5 wherein said operator control means includes a manually operable movable valve controlling communication between said inlet plenum and outlet plenum and means for moving said valve and placing said plenums in communication when said periodic transfer means causes said valve means to open said passage means.

9. A system according to claim 8 wherein said kinematic train includes a link extending into said chamber and said outlet plenum, a spring in said outlet plenum attached to said link, a rod secured to said spring and extending outwardly of said outlet plenum said valve movable with said rod wherein said spring is compressed and said rod moved so said valve places said plenums in communication and said valve means opens said passage means when pressure in said chamber is more than the predetermined amount.

10. A control system for a gas blown fog horn having as a source of energy a pressurized gas comprising an inlet plenum, means for continuously communicating said inlet plenum with a source of pressurized gas, an outlet plenum, means for continuously communicating said outlet plenum to a fog horn, operator control means for placing said inlet plenum and said outlet plenum in communication, means selectively operable for periodically and automatically transferring pressurized gas from a source of pressure to a fog horn, said selectively operable means including a chamber in restricted communication with a source of pressurized gas, pressure responsive means responsive to the pressure of gas in said chamber for periodically transferring gas to a fog horn when the pressure of the gas inside the chamber builds up to a predetermined pressure and for halting such transfer when the pressure of the gas inside the chamber has dropped to a lower predetermined pressure during such transfer.

11. A control system according to claim wherein a passageway is provided between the plenums and wherein a valve is in the passageway, said valve being controlled by said pressure responsive means.

12. A control system according to claim 10 wherein no direct connection is provided between the plenums, wherein a passageway is provided between the chamber and the outlet plenum and wherein a valve is in the passageway, said valve being controlled by said pressure responsive means.

13. A control system for a gas blown fog horn comprising:

a. a gas blown fog horn,

. a source of pressurized gas, an inlet plenum, means for continuously communicating said inlet plenum with said source of pressurized gas,

. an outlet plenum, means for continuously communicating said outlet plenum to said fog horn,

. operator control means for placing said inlet plenum and outlet plenum in communication; and

. pressure responsive means selectively operable for periodically and automatically transferring pressurized gas from said source of pressure to said fog horn with said pressure responsive means actuatable by pressurized gas from said source of pressure. 

1. A control system for a gas blown fog horn having as a source of energy a pressurized gas comprising: an inlet plenum, means for continuously communicating said inlet plenum with a source of pressurized gas, an outlet plenum, means for continuously communicating said outlet plenum to a fog horn, operator control means for placing said inlet plenum and said outlet plenum in communication, and pressure responsive means selectively operable for periodically and automatically transferring pressurized gas from a source of pressure to a fog horn with said pressure responsive means actuatable by pressurized gas from a source of pressure to a fog horn, said selectively operable means including a chamber, said chamber in continuous communication with said inlet plenum and means responsive to the pressure in the chamber for periodically transferring pressurized gas in said chamber to a fog horn.
 1. A control system for a gas blown fog horn having as a source of energy a pressurized gas comprising: an inlet plenum, means for continuously communicating said inlet plenum with a source of pressurized gas, an outlet plenum, means for continuously communicating said outlet plenum to a fog horn, operator control means for placing said inlet plenum and said outlet plenum in communication, and pressure responsive means selectively operable for periodically and automatically transferring pressurized gas from a source of pressure to a fog horn with said pressure responsive means actuatable by pressurized gas from a source of pressure to a fog horn, said selectively operable means including a chamber, said chamber in continuous communication with said inlet plenum and means responsive to the pressure in the chamber for periodically transferring pressurized gas in said chamber to a fog horn.
 2. A control system for a gas blown fog horn having as a source of energy a pressurized gas comprising an inlet plenum, means for continuously communicating said inlet plenum with a source of pressurized gas, an outlet plenum, means for continuously communicating said outlet plenum to a fog horn, operator control means for placing said inlet plenum and said outlet plenum in communication, means selectively operable for periodically and automatically transferring pressurized gas from a source of pressure to a fog horn, said selectively operable means including a chamber, said chamber in continuous communication with said inlet plenum, means responsive to the pressure in the chamber for periodically transferring pressurized gas in said chamber to a fog horn, said selectively operable means further including passage means communicating said chamber with said means for continuously communicating said outlet plenum to a fog horn, said periodic transferring means a flexible elastic member movable by the pressure in said chamber, valve means for opening and closing said passage means and a kinematic train connecting said flexible elastic member and said valve means.
 3. A control sysTem according to claim 2 wherein said kinematic train includes lost motion.
 4. A system according to claim 2 wherein means is provided for keeping said flexible elastic member in a position wherein said valve means closes said passage means.
 5. A system according to claim 2 wherein said flexible elastic member is a diaphragm, said chamber defined by a plurality of walls, one of said walls having an opening therein, said diaphragm secured to said wall so as to span said opening, said diaphragm prestressed so that when the pressure in said chamber is less than a predetermined amount the diaphragm snaps to a position wherein said valve means closes said passage means.
 6. A system according to claim 5 wherein said passage means communicated said chamber to said continuous means through said outlet plenum.
 7. A system according to claim 6 wherein said operator control means includes an opening extending between said inlet plenum and said outlet plenum, a valve for controlling the flow through said opening, and means manually operable for moving said valve to regulate the flow through said passageway.
 8. A system according to claim 5 wherein said operator control means includes a manually operable movable valve controlling communication between said inlet plenum and outlet plenum and means for moving said valve and placing said plenums in communication when said periodic transfer means causes said valve means to open said passage means.
 9. A system according to claim 8 wherein said kinematic train includes a link extending into said chamber and said outlet plenum, a spring in said outlet plenum attached to said link, a rod secured to said spring and extending outwardly of said outlet plenum said valve movable with said rod wherein said spring is compressed and said rod moved so said valve places said plenums in communication and said valve means opens said passage means when pressure in said chamber is more than the predetermined amount.
 10. A control system for a gas blown fog horn having as a source of energy a pressurized gas comprising an inlet plenum, means for continuously communicating said inlet plenum with a source of pressurized gas, an outlet plenum, means for continuously communicating said outlet plenum to a fog horn, operator control means for placing said inlet plenum and said outlet plenum in communication, means selectively operable for periodically and automatically transferring pressurized gas from a source of pressure to a fog horn, said selectively operable means including a chamber in restricted communication with a source of pressurized gas, pressure responsive means responsive to the pressure of gas in said chamber for periodically transferring gas to a fog horn when the pressure of the gas inside the chamber builds up to a predetermined pressure and for halting such transfer when the pressure of the gas inside the chamber has dropped to a lower predetermined pressure during such transfer.
 11. A control system according to claim 10 wherein a passageway is provided between the plenums and wherein a valve is in the passageway, said valve being controlled by said pressure responsive means.
 12. A control system according to claim 10 wherein no direct connection is provided between the plenums, wherein a passageway is provided between the chamber and the outlet plenum and wherein a valve is in the passageway, said valve being controlled by said pressure responsive means. 